1. Field of the Invention
The present invention relates to a chair adjustment device, and more particularly to an adjustment device of a chair with a foot ring.
2. Description of Related Art
With reference to FIG. 7, a foot ring 61 is mounted on a highchair or an office seat 60. The foot ring 61 has a mounting collar 62 mounted at a middle of the foot ring 61. The foot ring 60 can be mounted around a leg tube 63 of the office seat 60 via the mounting collar 62. The mounting collar 62 has a threaded hole radially formed in the mounting collar 62. The threaded hole is provided for combining with a fixing unit 64. The fixing unit 64 is combined with the threaded hole and is tightened to abut the leg tube 63 to fix a position of the foot ring 61 relative to the leg tube 63.
However, when the position of the foot ring 61 needs to be adjusted, the fixing unit 64 has to be loosened or tightened by a hand tool or a hand of a user. Therefore, the adjustment process is inconvenient for the user, especially for a user with relatively weak physical strength.
Furthermore, the leg tube 63 is a smooth cylinder, but the foot ring 61 is positioned around the leg tube 63 only by the fixing unit 64, such that only a point contact is formed between the fixing unit 64 and the leg tube 63. If the fixing unit 64 is too tightened for abutting the leg tube 63, the leg tube 63 may be damaged. On the other hand, in use, the foot ring 61 may withstand a considerable pedaling force from the user. When the pedaling force is insufficient, the foot ring 61 may be detached from the leg tube 63.